Assessment of the Incremental Diagnostic Value of Florbetapir F 18 Imaging in Patients With Cognitive Impairment: The Incremental Diagnostic Value of Amyloid PET With [18F]-Florbetapir (INDIA-FBP) Study.

IMPORTANCE: Cerebral amyloidosis is a key abnormality in Alzheimer disease (AD) and can be detected in vivo with positron emission tomography (PET) ligands. Although amyloid PET has clearly demonstrated analytical validity, its clinical utility is debated. OBJECTIVE: To evaluate the incremental diagnostic value of amyloid PET with florbetapir F 18 in addition to the routine clinical diagnostic assessment of patients evaluated for cognitive impairment. DESIGN, SETTING, AND PARTICIPANTS: The Incremental Diagnostic Value of Amyloid PET With [18F]-Florbetapir (INDIA-FBP) Study is a multicenter study involving 18 AD evaluation units from eastern Lombardy, Northern Italy, 228 consecutive adults with cognitive impairment were evaluated for AD and other causes of cognitive decline, with a prescan diagnostic confidence of AD between 15% and 85%. Participants underwent routine clinical and instrumental diagnostic assessment. A prescan diagnosis was made, diagnostic confidence was estimated, and drug treatment was provided. At the time of this workup, an amyloid PET/computed tomographic scan was performed, and the result was communicated to physicians after workup completion. Physicians were asked to review the diagnosis, diagnostic confidence, and treatment after the scan. The study was conducted from August 5, 2013, to December 31, 2014. MAIN OUTCOMES AND MEASURES: Primary outcomes were prescan to postscan changes of diagnosis, diagnostic confidence, and treatment. RESULTS: Of the 228 participants, 107 (46%) were male; mean (SD) age was 70.5 (7) years. Diagnostic change occurred in 46 patients (79%) having both a previous diagnosis of AD and an amyloid-negative scan (P < .001) and in 16 (53%) of those with non-AD diagnoses and an amyloid-positive scan (P < .001). Diagnostic confidence in AD diagnosis increased by 15.2% in amyloid-positive (P < .001; effect size Cohen d = 1.04) and decreased by 29.9% in amyloid-negative (P < .001; d = -1.19) scans. Acetylcholinesterase inhibitors and memantine hydrochloride were introduced in 61 (65.6%) patients with positive scan results who had not previously received those drugs, and the use of the drugs was discontinued in 6 (33.3%) patients with negative scan results who were receiving those drugs (P < .001). CONCLUSIONS AND RELEVANCE: Amyloid PET in addition to routine assessment in patients with cognitive impairment has a significant effect on diagnosis, diagnostic confidence, and drug treatment. The effect on health outcomes, such as morbidity and mortality, remains to be assessed.

18F-Fluorocholine PET/CT Finding of a Vertebral Hemangioma.

The uptake of F-fluorocholine (FCH), a radiopharmaceutical used to study patients with prostate cancer, follow both the phosphorylcholine and acetylcholine synthesis. FCH uptake is not specific of neoplastic cells because phospholipids are a structural constituent of the membrane of all cells. Thus, PET/CT with FCH show several areas of physiologic uptake. The skeleton concentrates only mild amounts of FCH, thus a diffuse faint uptake of the radiopharmaceutical is present at a PET/CT study. Herein we present the case of a patient in which PET/CT evidenced a sharply defined vertebral "cold" area of reduced FCH uptake corresponding to a vertebral hemangioma.

Feasibility of one-eighth time gated myocardial perfusion SPECT functional imaging using IQ-SPECT.

PURPOSE: IQ-SPECT, an add-on to general purpose cameras based on multifocal collimation, can reduce myocardial perfusion imaging (MPI) acquisition times to one-fourth that of standard procedures (to 12 s/view). In a phantom study, a reduction of the acquisition time to one-eighth of the standard time (to 6 s/view) was demonstrated as feasible. It remains unclear whether such a reduction could be extended to clinical practice. METHODS: Fifty patients with suspected or diagnosed CAD underwent a 2-day stress-rest (99m)Tc-sestamibi MPI protocol. Two consecutive SPECT acquisitions (6 and 12 s/view) were performed. Electrocardiogram-gated images were reconstructed with and without attenuation correction (AC). Polar maps were generated and visually scored by two blinded observers for image quality and perfusion in 17 segments. Global and regional summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS) were determined. Left ventricular volumes and ejection fraction were calculated based on automated contour detection. RESULTS: Image quality was scored higher with the 12 s/view acquisition, both with and without AC. Summed scores were statistically comparable between the 6 s/view and the 12 s/view acquisition, both globally and in individual coronary territories (e.g. in images with AC, SSS were 6.6 ± 8.3 and 6.2 ± 8.2 with 6 s and 12 s/view, respectively, p = 0.10; SRS were 3.9 ± 5.6 and 3.5 ± 5.3, respectively, p = 0.19; and SDS were 2.8 ± 5.7 and 2.6 ± 5.7, respectively, p = 0.59). Both acquisitions allowed MPI-based diagnosis of CAD in 25 of the 50 patients (with AC). Calculated end-diastolic volume (EDV) and end-systolic volume (ESV) were modestly higher with the 6 s/view acquisition than with the 12 s/view acquisition (EDV +4.8 ml at rest and +3.7 ml after stress, p = 0.003; ESV +4.1 ml at rest and +2.6 ml after stress, p = 0.01), whereas the ejection fraction did not differ (-1.2 % at rest, p = 0.20, and -0.9 % after stress, p = 0.27). CONCLUSION: Image quality and LV functional parameters obtained with a one-eighth acquisition time were statistically comparable to the previously validated one-fourth time protocol using IQ-SPECT. Shorter acquisition times without loss of diagnostic accuracy provide improved patient comfort and streamlined departmental efficiency.

Positron Emission Tomography for the Response Evaluation following Treatment with Chemotherapy in Patients Affected by Colorectal Liver Metastases: A Selected Review.

The aim of the present paper is to review the scientific literature concerning the usefulness of (18)F-FDG PET/CT in the evaluation of response to chemotherapy in patients affected by liver metastases from colorectal cancer. Material and Methods. Studies were identified by searching PubMed electronic databases. Both prospective and retrospective studies were included. Information regarding the figure of merit of PET for the evaluation of therapy response was extracted and analyzed. Results. Existing data suggests that (18)F-FDG PET/CT may have an outstanding role in evaluating the response. The sensitivity of PET in detecting therapy response seems to be greater than conventional imaging (CT and MRI). PET/CT response is strictly related to better overall survival and progression-free survival. Conclusions. PET/CT is more than a promising technique to assess the response to chemotherapy in colorectal and liver metastases. However, to be fully validated, this examination needs further studies by recruiting more patients.

A very unusual and aggressive form of a primary pulmonary meningioma seen with a 68Ga-DOTATOC PET/CT image / Una forma insólita y agresiva de meningioma pulmonar primario demostrada con 68Ga-DOTATOC PET/TC

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ImmunoPET in Neoplasms of Gastrointestinal Tract, Liver and Pancreas in the XXIst Century: Bridging the Gap Between Diagnosis and Therapy.

Monoclonal antibodies (mAbs) are produced by clones of a unique parent cell which has monovalent affinity and can bind to the same epitope. The chronological breakthrough in mAbs clinical utilization was in 1975, when it becomes possible to produce mAbs to known antigens and immortalize the cell lines. However, the clinical usefulness of mAbs was hampered for many years, basically because of their immunogenicity due to the murine origin. This situation lasted until 1988 when a technique to humanize mAbs was defined. Nuclear Medicine researchers were very quick to gathered the opportunity provided by the development of mAbs. The first papers reporting the preclinical use of radiolabelled mAbs date the early 80's soon followed by the first pivotal use in humans. However, mAbs did not gain a wide clinical use for several reasons connected to the chemistry and biochemistry of radiolabelled mAbs the emergence of clinical 18F-FDG PET. However, the "magic bullet" concept has resisted in the cultural background of Nuclear Medicine physicians for almost twenty years, and has regained importance with the development of engineered mAbs. Herein we present a selected review of preclinical and clinical studies of PET/CT with mAbs in gastrointestinal malignancies.

The importance of a correct positioning of the heart using IQ-SPECT system with multifocal collimators in myocardial perfusion imaging: a phantom study.

BACKGROUND: We have recently validated a quarter-time protocol in Myocardial Perfusion Imaging named IQ-SPECT, whose basic principle is to implement a multifocal collimator; However, in clinical practice, it may sometimes be difficult to center the heart in the region of highest magnification of the multifocal collimators (the so-called sweet spot). We therefore aimed to evaluate whether a heart mispositioning may affect results in MPI. METHODS: We simulated a rest study with an anthropomorphic phantom with an in vivo distribution of 400 MBq [(99m)Tc]tetrofosmin, with and without a transmural defect (TD). For each set of images, we performed 5 acquisitions, one with a correct centering and with other 4 degrees of mispositioning. Raw data and reconstructed images were evaluated qualitatively and quantitatively, including no corrections, correction for attenuation, for scatter or for both. We assessed polar plot uniformity, LV wall thickness, and TD and cavity contrast. RESULTS: Images obtained either with a correct heart centering or with mild misposition showed no differences, both qualitatively and quantitatively. Those obtained with major mispositioning differed in uniformity and TD contrast depending on correction parameters. CONCLUSION: This is the first study investigating how a heart mispositioning can affect diagnostic accuracy with IQ-SPECT system. Mild-to-moderate mispositioning (≤2.5 cm) is unlikely to significantly affect results.

The role of neuroimaging in evaluating patients affected by Creutzfeldt-Jakob disease: a systematic review of the literature.

Diagnosis of Creutzfeldt-Jakob disease during life can be challenging since the huge variability of the symptoms which can be observed, especially in its early stages, may simulate other common forms of dementia. In latest years, noninvasive techniques such as magnetic resonance, positron emission tomography, and single-photon emission tomography have been evaluated to help clinical neurologists to provide a definite diagnosis. We here provide a systematic review of the current knowledge of neuroimaging in CJD in order to establish the actual state of the art.

IQ SPECT allows a significant reduction in administered dose and acquisition time for myocardial perfusion imaging: evidence from a phantom study.

UNLABELLED: We recently demonstrated in a clinical trial the ability of a new protocol, IQ SPECT, to acquire myocardial perfusion imaging (MPI) studies in a quarter of the time (12 s/view) of the standard protocol, with preserved diagnostic accuracy. We now aim to establish the lower limit of radioactivity that can be administered to patients and the minimum acquisition time in SPECT MPI using an IQ SPECT protocol, while preserving diagnostic accuracy. METHODS: An anthropomorphic cardiac phantom was used to acquire clinical rest scans with a simulated in vivo distribution of (99m)Tc-tetrofosmin at full dose (740 MBq) and at doses equal to 50%, 25%, and 18%. For each dose, 2 sets of images were acquired, with and without a transmural defect (TD). Variable acquisition times were also used for each dose. We analyzed raw data and reconstructed images, including no correction and correction for attenuation (AC), for scatter (SC), or for both (ACSC). Images were evaluated qualitatively and quantitatively in order to assess left ventricle (LV) wall thickness (full width at half maximum of the medial sections), TD, and cavity contrast in the LV wall. Data were compared across different acquisition times within the same dose and across doses with the same acquisition time. RESULTS: Images were visually scored as very-good quality except those acquired with 4 s/view or less at 100% dose and 6 s/view or less with 50%, 25%, or 18% dose, due to false-positive defects. LV wall thickness was not significantly different among all acquisitions. Cavity contrast remained unchanged within the same dose for all images and tended to be higher in AC and ACSC images. TD contrast remained unchanged within the same dose for all images. In SC and no-correction images, contrast was constant for all doses. AC images had significantly higher TD contrast values, and ACSC images showed a drop in TD contrast for a 50% dose. CONCLUSION: IQ SPECT effectively preserved both image quality and quantitative measurements with reduced acquisition time or administered dose in a phantom study. These findings suggest that approximately one eighth of the time, compared with standard protocols with a full dose, or a lower dose at an acquisition time of 12 s/view can be applied in MPI without the loss of diagnostic accuracy.

Deep Inspiration Breath Hold [18F]FDG PET-CT on 4-rings scanners in evaluating lung lesions: Evidences from a phantom and a clinical study / [18F]FDG PET/TC en ausencia de respiración utilizando escáneres de 4 anillos en la valoración de lesiones pulmonares: evidencias de un estudio clínico y con maniquí

Objective: To investigate the clinical feasibility of a Deep Inspiration Breath Hold (DIBH) 18F-FDG PET-CT acquisition in apnea and compare the results obtained between these acts of acquisition in apnea and in Free Breathing in the evaluation of lung lesions. Material and methods: A pre-clinical phantom study was performed to evaluate the shortest simulated DIBH time according to the minimum detectable lesion that can be detected by our ultrasound scanner. This study was conducted by changing acquisition time and sphere-to-background activity ratio values and by using radioactivity densities similar to those generally found in clinical examinations. In the clinical study, 25 patients with pulmonary lesions underwent a standard whole body 18F-FDG PET-CT scan in free breathing followed by a 20 s single thorax acquisition PET/CT in DIBH acquisition. Results: The phantom study indicated that a 20-s acquisition time provides an accurate evaluation of smallest sphere shaped lesions. In the clinical study, PET-CT scans obtained in DIBH studies showed a significant reduction of misalignment between the PET and CT scan images and an increase of SUVmax compared to free breathing acquisitions. A correlation between the %BH-index and lesion displacement between PET and CT images in FB acquisition was demonstrated, significantly higher for lesions with a displacement > 8 mm. Conclusion: The single 20 s acquisition of DIBH PET-CT is a feasible technique for lung lesion detection in the clinical setting. It only requires a minor increase in examination time without special patient training. 20 s DIBH scan provided a more precise measurement of SUVmax, especially for lesions in the lower lung lobes which usually show greater displacement between PET and CT scan images in FB acquisition (AU)

Objetivo: Estudiar la viabilidad clínica de la adquisición 18F-FDG PET-TC en apnea y comparar los resultados obtenidos entre las adquisiciones en apnea y en respiración libre en la valoración de lesiones pulmonares. Material y métodos: Se ha realizado un estudio preclínico en maniquí con objeto de establecer el tiempo mínimo de adquisición en apnea en función de la más pequeña lesión evidenciable con nuestro tomógrafo. Este estudio se obtuvo modificando los tiempos de adquisición y la relación de actividad entre esfera y fondo utilizando actividades parecidas a las encontradas en la práctica clínica. En el estudio clínico, 25 pacientes con lesiones pulmonares fueron evaluados mediante PET-TC con 18F-FDG en respiración libre y posteriormente en apnea de 20 segundos. Resultados: El estudio en maniquí indicó que una adquisición de 20 segundos es adecuada para la valoración de las esferas más pequeñas. En el estudio clínico, las adquisiciones PET-TC obtenidas en apnea mostraron una significativa reducción de la desalineación entre la imagen PET y la imagen TC y un incremento en el valor del SUVmax respecto a las adquisiciones en respiración libre. Hemos demostrado la existencia de correlación entre el %BH-index y la desalineación en respiración libre, significativamente mayor en las lesiones con desalineación superior a 8 mm. Conclusiones: La adquisición PET-TC de 20 segundos en apnea es una técnica viable para la detección de la lesión pulmonar en el entorno clínico y requiere solo un pequeño aumento en el tiempo de examen sin requerir especial entrenamiento del paciente. La adquisición en apnea aporta una medida más precisa del SUVmax, especialmente en las lesiones de los lóbulos inferiores que normalmente presentan una marcada desalineación entre las imágenes PET y TC (AU)

Intense uptake evidenced by 18F-FDG PET/CT without a corresponding CT finding--dream or reality?

Although 18F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) has been widely validated and extensively used in the latest years in clinical practice, interpretation of PET/CT images can be affected by several pitfalls. We here present a case of intense lung uptake in a patient without a corresponding finding on CT images, probably due to a microembolism produced during the injection process and located in small vascular structures of the lung parenchyma.

Unusual widespread metastatic subcutaneous lesions in a patient with ileal carcinoid evidenced by 68Ga-DOTATOC PET/CT.

68Ga-DOTATOC PET/CT has been widely validated in diagnosis and follow-up of carcinoid. A 47-year-old woman with ileal carcinoid underwent a 68Ga-DOTATOC PET/CT for restaging purposes. Images showed extensive liver involvement and also a widespread metastatic subcutaneous metastases in the right chest wall and in the right laterocervical region. The presence of multiple soft-tissue metastases, as described in our case and imaged with 68Ga-DOTATOC, represents a very rare clinical entity.

Deep Inspiration Breath Hold [(18)F]FDG PET-CT on 4-rings scanners in evaluating lung lesions: evidences from a phantom and a clinical study.

OBJECTIVE: To investigate the clinical feasibility of a Deep Inspiration Breath Hold (DIBH) (18)F-FDG PET-CT acquisition in apnea and compare the results obtained between these acts of acquisition in apnea and in Free Breathing in the evaluation of lung lesions. MATERIAL AND METHODS: A pre-clinical phantom study was performed to evaluate the shortest simulated DIBH time according to the minimum detectable lesion that can be detected by our ultrasound scanner. This study was conducted by changing acquisition time and sphere-to-background activity ratio values and by using radioactivity densities similar to those generally found in clinical examinations. In the clinical study, 25 patients with pulmonary lesions underwent a standard whole body (18)F-FDG PET-CT scan in free breathing followed by a 20s single thorax acquisition PET/CT in DIBH acquisition. RESULTS: The phantom study indicated that a 20-s acquisition time provides an accurate evaluation of smallest sphere shaped lesions. In the clinical study, PET-CT scans obtained in DIBH studies showed a significant reduction of misalignment between the PET and CT scan images and an increase of SUVmax compared to free breathing acquisitions. A correlation between the %BH-index and lesion displacement between PET and CT images in FB acquisition was demonstrated, significantly higher for lesions with a displacement>8mm. CONCLUSION: The single 20s acquisition of DIBH PET-CT is a feasible technique for lung lesion detection in the clinical setting. It only requires a minor increase in examination time without special patient training. 20s DIBH scan provided a more precise measurement of SUVmax, especially for lesions in the lower lung lobes which usually show greater displacement between PET and CT scan images in FB acquisition.

Extraosseous myocardial uptake incidentally detected during bone scan: report of three cases and a systematic literature review of extraosseous uptake.

Bone scintigraphy is widely considered as an important technique able to investigate various pathological conditions of the skeletal system. Many unexpected extraosseous uptakes have been reported in literature. We present here three cases of unexpected 99mTc-oxidronate (HDP) myocardial extraosseous uptakes in patients undergoing bone scan for staging purposes. In particular, we present the first reported case ofa myocardial uptake in a patient with IgM-related amyloidosis. Subsequently, we perform a review of the existing literature about extraosseous uptakes.

Proposal for an optimized protocol for intravenous administration of insulin in diabetic patients undergoing (18)F-FDG PET/CT.

The objective of this study was to evaluate the usefulness and impact of insulin administration before an F-FDG PET/computed tomography (CT) examination in diabetic patients in order to propose an optimized protocol that can reduce blood glucose levels without increasing muscular F-FDG uptake. A total of 130 patients underwent an F-FDG PET/CT. Twenty patients had glucose levels greater than 180 mg/dl and received endovenous insulin before F-FDG injection (group 1); 10 patients had glucose levels greater than 160 mg/dl and lower than 200 mg/dl and received no insulin (group 2); 100 patients were euglycemic (group 3). Biodistribution was adequate in 19 of 20 patients in group 1. Values of standardized uptake value in the gluteal muscle were 0.50±0.18 for group 1, 0.48±0.10 for group 2, and 0.49±0.08 for group 3; no significant differences in muscular F-FDG uptake could be found among the three groups. No adverse events were recorded. In conclusion, our protocol has been demonstrated to be safe and effective, with only a minor impact on glucose biodistribution and apparently without affecting PET accuracy.

Unsuspected Active Sarcoidosis Diagnosed by 18F-FDG PET/CT During the Search for a Primary Tumour in a Patient with Bone Lesions.

Sarcoidosis is a systemic chronic inflammatory disease of unknown aetiology, characterised by granulomatous lesions with heterogeneous clinical manifestations affecting multiple organs and tissues. Although the respiratory system is most commonly affected, the disease may also present with bone lesions. We report the case of a 31-year-old woman who presented with low back pain and no history of cancer and who was found to have suspicious lesions involving the entire spine on magnetic resonance imaging (MRI). The patient underwent 18F-fluorodeoxyglucose (FDG) PET/CT to search for a primary tumour and for staging purposes. 18F-FDG PET/CT revealed a pattern of hypermetabolic activity in widespread skeletal lesions and in a single left cervical lymph node. The primary tumour was not found, thus suggesting a haematologic disorder. Subsequent biopsies of a cervical lymph node and of bone tissue from L4 revealed active sarcoidosis with no evidence of cancer. This underlines the importance of considering all alternatives when hypermetabolic lesions are found on 18F-FDG PET/CT. Furthermore, 18F-FDG PET can be very useful to indicate accessible sites for guiding fine-needle aspiration cytology (FNAC).